Method for manufacturing rotary electric system

ABSTRACT

A winding on a stator of a rotary electric machine is constructed by welding end portions of a plurality of segments. A plurality of pairs arranged on an end of the stator are welded by a welder. In a welding stage, the pairs are held by a plurality of insertion rods of a circumferential side holding tool. The insertion rods are radially disposed. The insertion rods are movable in a radial direction. The insertion rods are moved back toward a radial outside to release a holding of the pairs after ball-shaped welding marks are formed. Holding is released without damage on the welding mark.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. Hei11-89790 filed on Mar. 30, 1999 and No.Hei 11-366258 filed on Dec. 24,1999 the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a rotaryelectric machine, particularly, to a method for manufacturing a windingthereof. This method is preferable for manufacturing a stator of avehicular AC generator mounted on a vehicle, a truck or the like.

2. Description of Related Art

Conventionally, in the art of the rotary electric machine, it is knownthat an entirety of a winding wound and disposed on a core isconstructed from a plurality of segments. In such a construction, aplurality of segments are fitted on the core. After that, the winding ismanufactured by joining these segments. Soldering, welding, brazing orthe like is used as a joining method. In the case of welding, arcwelding, laser welding, electron beam welding or the like may be used.

In a case that joining process for a plurality of points are executed inthe manufacturing method of the rotary electric machine, it is requiredto execute a large number of joining at high speed. Additionally, toimprove an industrial productivity, it is necessary to execute a largenumber of joining reliably and speedily. Specifically, it is necessaryto fix and hold a plurality of joining points in desired positionefficiently, to execute the joining work under a holding condition andto release the holding condition without a damage on the joiningportion.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a manufacturingmethod of a rotary electric machine for joining a plurality of joiningpoints at high speed.

It is a further object of this invention to provide a manufacturingmethod of a rotary electric machine for joining a plurality of joiningpoints reliably.

It is another object of this invention to provide a manufacturing methodfor holding a plurality of joining points efficiently, and for releasinga holding condition without a damage on the joining point after joining,even in a case that the joining work is executed on the plurality ofjoining points.

According to the present invention, a plurality of holding tools aredisposed in between pairs of end portions to be joined, and the holdingtools are moved back in a direction crossing an extending direction ofthe end portions to release holding. It is possible to hold theplurality of pairs to be joined efficiently, and to prevent a damage ona joining mark. The moving direction of the holding tool may be at aright angle against the extending direction of the end portion.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating preferred embodiments of the invention, are intended forpurposes of illustration only, since various changes and modificationswithin the spirit and scope of the invention will become apparent tothose skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view showing an outside appearance of a statorof a rotary electric machine of a first embodiment of the presentinvention;

FIG. 2 is an enlarged perspective view of a part of FIG. 1, showing anappearance before welding of the first embodiment;

FIG. 3 is a perspective view showing a shape of a segment of the firstembodiment;

FIG. 4 is a perspective view showing a welding stage of the firstembodiment;

FIG. 5 is a perspective view showing an insertion rod of acircumferential side holding tool of the first embodiment;

FIG. 6 is a perspective view showing an inserting stage of the insertionrod of the first embodiment; and

FIG. 7 is a plan view showing the insertion rod from an arrow directionVII in FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereafter, an embodiment will be described based on the drawings. Thepresent invention is applied to a manufacturing method of a statorwinding for a vehicular AC generator as a rotary electric machine.

A stator 1 of the vehicular AC generator has a cylindrical stator core11. The stator core 11 is formed by laminating a plurality of steelsheets. A plurality of slots 12 are formed to extend in the axialdirection on the inside surface of the stator core 11. A stator winding13, which is a winding, is positioned in the slots 12. The statorwinding 13 is a three phase winding as a poly-phase winding. The statorwinding 13 forms a first coil end group 13 a on one axial end of thecore 11. The winding 13 forms a second coil end group 13 b on the otheraxial end of the core 11. The winding 13 is constructed of a pluralityof segments made of copper wire. The segments are disposed in each ofthe slots 12 as conductors. Further, insulating sheets 14 are disposedin between each of the slots 12 and the electric conductors disposedtherein.

The winding 13 is formed by joining the segments. In this embodiment,U-shaped segments 15 shown in FIG. 3 are mainly used. I-shaped segmentscan be used alternatively. The U-shaped segments shown in FIG. 3 areformed by bending a conductor wire having a flat cross-section into aU-shape, and twisting both arm portions at a designated position in adesignated direction. In this embodiment, the U-shaped segmentsincluding a small and a large types as shown in FIG. 3 are used. TheU-shaped segments are twisted as indicated by arrows A and inserted fromone axial end of the core 11. After that, end portions 16 extended fromthe other axial end of core 11 are twisted as indicated by arrows B.Therefore, the U-shaped segments form the coil end group 13 a as shownin FIG. 2. The end portions 16 have skew portions 16 a extendingobliquely, tip portions 16 b extending axially, and end surfaces 16 cthereon. The tip portions 16 b are provided for a joining stage.

In this embodiment, four segments are disposed in one slot to make fourlayers in the radial direction. As a result, in the first coil end group13 a, four end portions to be joined 161, 162, 163 and 164 are alignedin the radial direction. Two end portions to be joined 161, 162, whichare adjacent in the radial direction, form a pair 17 (17 a) of the tipto be joined. Two end portions to be joined 163 and 164, which areadjacent in the radial direction, also form a pair 17 (17 b) of the tipto be joined. In this embodiment, the pairs 17 are arranged on a line tomake a ring 18. Additionally, the pairs 17 form multiple coaxial ringsof different diameters. The pairs 17 are arranged on two parallel ringlines which are a plurality of parallel lines. The plurality of outerpairs 17 a make an outer ring 18 a. The plurality of inner pairs 17 bmake an inner ring 18 b.

A continuous winding disposed around the stator core 11 is formed byjoining the pairs 17 disposed as shown in FIG. 2.

Next, manufacturing process of the stator will be described. At first,the stator core 11 is manufactured. Secondly, the process proceeds to astage for inserting the plurality of segments 15 on the core 11 and astage for arranging the plurality of pairs. In this stage, the segments15 are inserted into the slots 12 from one of the axial end of thestator core 11. The plurality of end portions 16 extended from the otherend of the core 11 are twisted as shown in FIG. 2. The end portions 16are arranged as shown in FIG. 2 by the twisting process. Two tips arearranged in the radial direction as the pair 17. Next, a holding stageand a welding stage are carried out. Two end portions 16 areelectrically joined by welding the pairs 17. As a result, the winding isformed by connecting the plurality of segments 15 in series.

Next, the holding stage and the welding stage are described in detail.In the holding stage, at first, the stator assembly processed into theshape shown in FIG. 2 is held and fixed. The stator core 11 is fixed ona core fixing device 21. Next, the pairs 17 are held and fixed in thedesignated shape and position shown in FIG. 2 by a plurality of holdingtools, including an inside holding tool 23, an outside holding tool 24and a circumferential side holding tool 25. These holding tools 23, 24,25 also act as electrodes to supply electric current for welding.

The inside holding tool 23 is constructed in a disk shape. The insideholding tool 23 is an assembly of a plurality of fan-shaped portions.The fan-shaped portions are movable toward inside and outside in theradial direction by a driving device 23 a. The inside holding tool hasan upper portion 23 b and a lower portion 23 c, and has a plurality ofholes 23 d therebetween. The holes 23 d are disposed as a plurality ofcoupling portions radiating in all directions. The holes 23 d opentoward a radial outside. The inside holding tool 23 defines a radialinside position of the plurality of pairs 17 arranged on the radialdirection. The inside holding tool 23 contacts a radial inside surfaceof the end portion 164 positioned on the most inside.

The outside holding tool 24 is constructed in a ring shape. the outsideholding tool 24 is an assembly of a plurality of fan-shaped portions.The fan-shaped portions are movable toward inside and outside in theradial direction by a driving device 24 a. The outside holding tool hasa movable portion 24 b. The outside holding tool 24 defines a radialoutside position of the plurality of pairs 17 arranged on the radialdirection. The outside holding tool 24 contacts a radial outside surfaceof the end portion 161 positioned on the most outside.

The circumferential side holding tool 25 is constructed by a pluralityof insertion rods disposed radially. Each of the insertion rod ismovable toward inside and outside in the radial direction by a drivingdevice 25 a. The circumferential side holding tool 25 has a plurality ofinsertion rods 25 b disposed to extend in all directions. In thisembodiment, the plurality of insertion rods move in the radial directionall together by the driving device 25 a. The moving direction of theinsertion rods 25 b crosses the direction of extension of the pairs 17.The crossing angle is at right. The driving device can be so constructedthat the plurality of insertion rods 25 b are moved in sequence. Thedriving device can be also constructed to provide the followingmovements: the plurality of insertion rods are moved in the axialdirection to insert it into recesses between the plurality of pairs 17when the plurality of insertion rods 25 b are installed; and theplurality of insertion rods are moved in the radial direction toward theoutside to pull it out when the plurality of insertion rods 25 b areuninstalled.

Each of the insertion rods 25 b has a first portion 25 c tapered off tothe tip and a wider second portion 25 d positioned on radial outside.The first portion 25 c has a width corresponding to a distance betweenthe tip portions 16 b of two pairs 17 which are adjacent in thecircumferential direction. The first portion 25 c is disposed betweentwo pairs 17 which are adjacent in the circumferential direction. Thesecond portion 25 d is protruded in one side of the circumferentialdirection to form a step portion from the first portion 25 c. A surface25 e provided by the step portion defines the radial outside position ofthe plurality of pairs 17 arranged in the radial direction. The surface25 e contacts the radial outer surface of the end portion 161 positionedin the most outside. The tip of the insertion rod 25 b can be insertedinto and coupled with the hole 23 d of the inside holding tool 23. Theplurality of insertion rods 25 b are radially positioned and fixed inits designated position by inserting the tip of the insertion rod 25 binto the hole 23 d. The tip is coupled tightly in both thecircumferential and axial directions. The coupling on thecircumferential direction is more important than the axial direction foran accurate positioning. The plurality of insertion rods, forming thecircumferential side holding tool 25, can be constructed integrally withthe outside holding tool 24.

In this embodiment, the insertion rods 25 b are installed betweenadjacent pairs 17 to make an appearance shown in FIG. 4 by moving it toinsert from the radial outside. AS shown in FIG. 6, the first portion 25c of the pairs 25 b has a cross sectional shape corresponding to a shapeof gutters on an inserting path. The gutters are formed by the pluralityof end portions 161, 162, 163 and 164. As shown in FIG. 7, the firstportion 25 c of the insertion rod 25 b appears like a bottom of ship inthe view from the tip. The first portion 25 c has a cross section shapedas the home base corresponding to a shape of the skew portion 16 a andthe tip portion 16 b. The first portion 25 c is made of a smooth surfacenot to damage the end portions. The shape of the end portions aremodified into the designated proper shape by inserting such theinsertion rods 25 b.

A function of this embodiment will be described referring to, forinstance, the case that the end portion 162 is bent more than thedesignated proper shape shown by the broken line in FIG. 7. With theinsertion of the first portion 25 c, the end portion 162 is modified bybending along the cross section of the first portion 25 c. As a result,the end portion 162 is modified into the designated proper positionshown by the solid line. Therefore, the pairs 17 are held and fixed inthe designated proper positions by the holding tools. The insertion rod25 b is contacted both of the pairs 17 a and 17 b belonging to the outerring 18 a and the inner ring 18 b. After that, the plurality of pairs 17are welded respectively.

In the welding stage, at first, a TIG welder head 3 is positioned todirect toward a top end of the pair 17. Next the welding current issupplied between the head 3 and the holding tools 23, 24 and 25 togenerate an arc. The top end of the pair 17 is melted into a fusion bythe arc. The pair 17 was just arranged before it melts. The head 3 ismoved to the next pair after it melts a predetermined amount. In thisembodiment, the relative movement between the head 3 and the pluralityof pairs 17 is provided by holding the head 3 and rotating the stator 1with the holding tools in a direction indicated by the arrow in FIG. 4.This direction may be reversed. On the top of the pair 17, a weldingmark 19 is formed as a joining mark by solidifying the melted copperagain. Therefore, the pair of the end portions constituting the pair 17are electrically connected. The welder is continuously activated duringthe head 3 moves around the plurality of pairs 17 while being directedthereon. As a result, the arc passes over around the plurality of pairsaligned on the line, and weld them around. In this embodiment, theplurality of pairs 17 forming the outer ring 18 a are continuouslywelded after the plurality of pairs 17 forming the inner ring 18 b arecontinuously welded. FIG. 4 shows the welding stage of the outer ring 18a. As the welding stage, plasma welding, gas welding, laser welding,electric resistance welding or the like may be used except for arcwelding.

After completion of the welding stage, on the top of the pair 17, thewelding mark 19 having larger diameter than the pair 17 is formed. Thewelding mark 19 is substantially a ball shape due to the surface tensionbefore it solidifies. The welding mark 19 projects in thecircumferential and radial directions relative to the end portion 17which is not welded. A melting range is preferably limited to prevent anenlargement of the welding mark 19. However, there is a limit to makethe melting range small, because of a strength and an electricresistance on the welding mark 19. Then, the welding mark 19 will be theabove-mentioned shape.

After completion of the welding stage, the holding tools 23, 24 and 25are moved back to release the holding of the pairs 17. After that, thewelded stator 1 is taken out. The process proceeds to a next coatingstage for the welding mark 19. Then, the stator 1 is assembled into thevehicular AC generator as the rotating electric machine.

In this embodiment, the insertion rods 25 b are inserted with rubbing onthe side surface of the end portions 16 when the insertion rods 25 b areinstalled. Therefore, it is easy to provide electric conduction betweenthe insertion rods 25 b and each end portion 16. Further, in the stagefor releasing the holding of the plurality of end portions 17, theinsertion rods 25 b, which is a circumferential side holding tool, aremoved radially outside. Therefore, it is prevented to make aninterference such as the collision between the welding mark 19 and thecircumferential side holding tool 25. As a result, a damage on thewelding mark 19 is prevented. It is also prevented to deform the weldedend portion 16. Further, a damage on an insulating film covering thecopper wire forming the segment 15 is prevented.

Although the present invention has been described in connection with thepreferred embodiments thereof with reference to the accompanyingdrawings, it is to be noted that various changes and modifications willbe apparent to those skilled in the art. Such changes and modificationsare to be understood as being included within the scope of the presentinvention as defined in the appended claims.

What is claimed is:
 1. A method for manufacturing a rotary electricmachine comprising a core and a plurality of conductors positioned onsaid core and provided as a part of a winding, the method comprising thesteps of: arranging a plurality of pairs into a ring, said pairscomprising end portions of said conductors to be joined and extendingfrom said core; holding said plurality of pairs by disposing holdingtools in between circumferentially adjacent two pairs to contact both ofsaid pairs respectively; joining the plurality of pairs under a holdingcondition of said pairs; and releasing the holding condition of thepairs by moving the holding tools in a direction crossing an extendingdirection of said end portions.
 2. A method for manufacturing a rotaryelectric machine according to claim 1, wherein: a joining mark is formedin said joining step, the joining mark is larger than an end of anon-joined pair.
 3. A method for manufacturing a rotary electric machineaccording to claim 1, wherein: said plurality of pairs are arranged toextend in an axial direction from said core in said arranging step.
 4. Amethod for manufacturing a rotary electric machine according to claim 3,wherein: two of said end portions to be joined are arranged in a radialdirection of said core in said arranging step.
 5. A method formanufacturing a rotary electric machine according to claim 3, wherein:said holding tools are moved in the radial outside direction relative tothe ring arrangement of said pairs in said releasing step.
 6. A methodfor manufacturing a rotary electric machine according to claim 1,wherein: said holding tools are inserted between said plurality of pairsby moving in a radial direction relative to a ring arrangement of saidpairs in said holding step.
 7. A method for manufacturing a rotaryelectric machine according to claim 1, wherein: a plurality of segmentsare positioned on said core as said conductors in said arranging step.8. A method for manufacturing a rotary electric machine according toclaim 7, wherein: U-shaped segments are inserted in said core from oneaxial end of said core to provide a plurality of end portions extendingfrom the other axial end of said core in said arranging step.
 9. Amethod for manufacturing a rotary electric machine according to claim 1,wherein: said plurality of pairs are arranged into a multiple coaxialrings on one axial end of said core in said arranging step.
 10. A methodfor manufacturing a rotary electric machine according to claim 9,wherein: one of said pairs belonging to said inner ring and one of saidpairs belonging to said outer ring are contacted with a common piece ofsaid holding tool extending in the radial direction in said holdingstep.
 11. A method for manufacturing a rotary electric machine accordingto claim 1, wherein: said end portion positioned on an end of a radialdirection is held relative to the radial direction by said holding toolin said holding step.
 12. A method for manufacturing a rotary electricmachine according to claim 1, wherein: a tip of said holding toolpositioned between said pairs is coupled with a coupling portion to fixthe holding tool in said holding step.
 13. A method for manufacturing arotary electric machine according to claim 1, wherein: said end portionis modified into a designated proper shape by using a cross sectionalshape of said holding tool corresponding to said designated proper shapeof said end portion in said holding step.
 14. A method for manufacturinga rotary electric machine comprising a core and a plurality ofconductors positioned on said core and provided as a part of a winding,the method comprising the steps of: arranging a plurality of pairs intoa ring, said pairs comprising end portions of said conductors to bejoined and extending from said core; holding said plurality of pairs bydisposing holding tools in between circumferentially adjacent two pairsto contact both of said pairs respectively; joining the plurality ofpairs under a holding condition of said pairs; and releasing the holdingcondition of the pairs by moving the holding tools in a directioncrossing an extending direction of said end portions, wherein saidplurality of pairs are arranged to extend in an axial direction fromsaid core in said arranging step, and wherein said holding tools aremoved in the radial outside direction relative to the ring arrangementof said pairs in said releasing step.
 15. A method for manufacturing arotary electric machine comprising a core and a plurality of conductorspositioned on said core and provided as a part of a winding, the methodcomprising the steps of: arranging a plurality of pairs into a ring,said pairs comprising end portions of said conductors to be joined andextending from said core; holding said plurality of pairs by disposingholding tools in between circumferentially adjacent two pairs to contactboth of said pairs respectively; joining the plurality of pairs under aholding condition of said pairs; and releasing the holding condition ofthe pairs by moving the holding tools in a direction crossing anextending direction of said end portions, wherein said holding tools areinserted between said plurality of pairs by moving in a radial directionrelative to a ring arrangement of said pairs in said holding step. 16.The method for manufacturing a rotary electric machine according toclaim 15, wherein: the plurality of pairs of the end portions arearranged into two rings that are coaxially positioned on an axial end ofthe core in the arranging step; and each of the holding tools isinserted between the pairs belonging to an inner ring and between thepairs belonging to an outer ring in the holding step.
 17. The method formanufacturing a rotary electric machine according to claim 16, whereinthe pairs belonging to the inner ring are further held by positioning aninside holding tool on a radial inside of the inner ring, and the pairsbelonging to the outer ring are further held by positioning an outerholding tool on a radial outside of the outer ring.
 18. The method formanufacturing a rotary electric machine according to claim 15, wherein:four of the end portions are arranged radially to provide two of thepairs in the arranging step; the holding tool is inserted tocircumferentially hold all of the radially arranged four end portions inthe holding step; an outside holding tool is positioned to radially holdthe end portion positioned most outside in the holding step; and aninside holding tool is positioned to radially hold the end portionpositioned most inside in the holding step.
 19. The method formanufacturing a rotary electric machine according to claim 15, whereinthe holding tools are inserted simultaneously.
 20. The method formanufacturing a rotary electric machine according to claim 15, whereinthe holding tools are moved in a radial direction in the releasing step.